Process and apparatus for the treatment of photographic coatings



May 6, 1941.v

PROCESS AND APPARATUS FOR THE '.IREATMENI. OF PHOTOGRAPHIC COATINGSFiled April 22, 193.9' 2 ShJets--Shee'I 2 vF7C-b9 #76:10

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L P. F. VAN DER GRlNTEN 2,241,104 Y Patented May 6, 1941 UNITED STATESPATENT. OFFICE PROCESS AND APPARATUS FOR THE TREAT- DIENT OFPHOTOGRAPHIC CQATHNGS Application April 22, 1939, Serial No. 269,430 Inthe Netherlands January 19, 1939 25 Claims. (Cl. SiS- 88) The presentinvention relates to processes and apparatus for the preparation,development or fixing of photographic coatings or layers on sheets ofany length according to the so-called semi-Wet method.

In the various reproduction processes, especally in making technicalreproductions, it is customary to treat material that has been exposedto light, for instance, light-sensitive paper, on one side with a liquidwhich develops and/or fixes the picture.

While one of the oldest known procedures Jfor the development of silverhalide paper is to ap ply an excess of liquid to the paper with the aidof a roller, (see German Patent No. 198,143), the so-called thin layeror semi-we method of development has recently been used to a greaterextent. With this semi-Wet method a definite quantity of liquid isapplied, and by this means, depending upon the concentration ofchemicals in the solution, a definite amount of chemicals is applied persurface unit of the material to be developed and/or fixed. This methodhas been described in various publications, including Chemie enIndustrie (1927), pages 235 and 257, Dutch Patent No.A 27,513, BritishPatent No. 326,568 and British Patent No. 416,489. In general, a rolleris used which rotates in a liquid bath, and the material to be developedis passed over this roller. 'I'he surface of the roller is geni erallysmooth, 'but may also be matted (see German Patent No. 664,916). Thevpaper is kept in touch with the roller, for example, by means of a comb(Dutch Patent No. 23,602), by small rotatingv disks (German Patent No.561,142 and U. S. Patent No. 1,891,722) or by means of a guide (FrenchPatent No. 692,658). In these, as well as in other processes, the paperruns freely over the roller. Such is not the case, however, with themethod of operation described in British Patent No. 295,993, where thepaper runs between two rollers which press against each other. In orderto handle sheets, means are often employed which lift the wetted sheetsoff the roller. So in the British Letters Patent 295,993, knivesperforming the role of cutters run in grooves of the caoutchouc roller,said grooves, .of course, closing in the soft caoutchouc and being at aconsiderable distance one from the other. In the British Letters Patent326,568 the application roller, for the purpose of arranging cutters, isprovided with canals which, however, again are within a considerabledistance from each other; these canals are, besides, relatively broad.

It is, furthermore, known that iilms may be provided `with a layersensitized to light by passing same across a relatively broad canal inwhich the surface of the liquid is always kept exactly on the upper edgeby a communicating connection with a supply vessel having a constantlevel. This requires that the canal be arranged exactly horizontally.

The semi-wet process also is used to apply sensitiaed coatings. Atypical example is the application of a coating of chromate gelatine orchromate gum to metal plates or metallized sheets for the Well-knownoiiice offset machines. The liquid layer is applied by pouring it onto ahorizontal .leaf or sheet, which is placed on a whirler so that theexcess liquid is flung off and a uniform layer remains. This process,however, is unwieldy, unreliable and uneconomical.

In the use of these known processes, several dii'liculties areencountered, especially when dealing with sheets of smaller lengths.

In general, not all papers or other materials undergoing treatment needthe same quantity of chemicals for proper treatment, and it is impossible, for example, without anything further, to develop a certaindiazoy type which requires 12 grams per square meter of a certaindeveloper, by applying 6 grams per square meter of a developer in adoubled concentration. The latter may at times penetrate the materialinsuiiicient- 1y, or it may crystallize out in the cold in such aconcentration.

Conditions are similar when processing other materials according to thesemi-wet method; for instance, when fixing blue prints. In that case,large quantities of the xing agent, for instance about 30 grams persquare meter, are required according to the present practice in the art.In general, it is desirable to apply the chemicals necessary for thetreatment by means of as little liquid as possible per unit area of thematerial, and in that case, therefore. the amount of liquid depends onthe chemicals to be applied. When dealing with different diazo typepapers and different chemical materials different quanti-ties of liquidare often desirable, and for that reason it would be of considerableadvantage to be able to regulate the amount of the liquid. In the knownprocesses, however, the amount of liquid to be applied to the paper bymeans of 'the roller is either incapable of being regulated in practice,or can be regulated only by means that are not always desirable. Forinstance, larger quantities, above about 20 g. per m3, can be obtainedonly by means of strong movement of the roller in a direction oppositeto f ing not entirely harmless. Besides the possibility of applyinglarger and larger quantities of liquid, the possibility of applyingsmaller and even very small quantities is at times of great importance.

Furthermore, when using the known. methods the amount of liquid appliedon the sheet by means of the roller, per squaremeter of surface area, isnot uniform from start to finish. In the beginning, the paper takesalong the smallest amount of liquid. This amount increases during thetreatment until it reaches a certain value, after which it remainsuniform during the further treatment of the particular sheet. Forinstance, if a sheet din A4 of a certain vpaper is developed in themanner described' in Dutch Patent No. 27,513, by means of apparatus suchas described in Dutch Patent No. 23,602, it is found upon examinationthat only 6 grams of the fluid are applied per square meter oi paper inthe beginning and that this quantity increases slowly until it reaches avalue of 12 grams per square meter at a distance of approximately 20 cm.from the start of the sheet. This phenomenon is referred to hereinafteras the stai-ting" and the aected portion of the sheet as the starten Adistinction is made between the length and the size of the starter. Bythe length is meant the number of centimeters of the paper which mustrun overl the roller before the maximum amount of liquid is applied. Theratio between the above indicated maximum amount of liquid and theamount of liquid which the paper takes on at the start of the treatmentrepresents the size of the starter. In the above-mentioned example,therefore, the length of the starter amounts to 20 cm., and the size toThe shortest starter, therefore, is naught; the minimumsizeisimity.Astarterisespecially annoying on sheets of smaller lengths in view ofthe fact that no pieces can be discarded therefrom. The application oftoo little liquid may result in underdevelopment and the application oftoo much liquid, for instance, in a yellowing of the prints.

It is one of the objects of the present invention to provide a new andimproved process for applying "semi-wet coatings of liquid to sheets ofany length in the preparation, development and/or fixing of photographiccoatings, which to a large extent overcomes the disadvantages mentionedhereinabove. More specifically, one of the objects of -the invention isto provide a new process by which definite amounts of the liquid may beapplied per unit area of the sheet.

Another object is to provide such a process in which the application ofthe liquid may be regulated to suit the requirements of dierent sheetmaterials and of different coating liquids.

Another object of the invention is to provide such` a -process whichVsubstantially reduces the difficulties heretofore encountered at thestart of each sheet by reducing both the "length and the size" of the"starter, thereby producing sheets characterized by improved uniformityand quality oi treatment.

A further object of the invention is to provide a process having thequalities just mentioned which at the same time is practical and eicientto operate.

Still another object of the invention is to provide new and improvedapparatus for applying semi-wet coatings of liquid to sheets of anylength in the preparation, development and/or fixing of photographiccoatings according to the process herein disclosed.

In accordance with this invention I have found that the foregoing andother valuable objects and advantages may be attained and that in thepreparation, development and/or fixing of photographic coatingsaccording to the semi-wet process highly uniform coatings may be formedon sheet material of any length by feeding the material over mechanismfor applying the liquid coating and by leading the liquid in amultiplicity of minute canals to the place where the material leaves theapplying mechanism. The multiplicity of minute canals are located soclose together that a substantially uniform layer or coating is appliedover the entire width of the sheet. The sheet is preferably passedfreely over the mechanism.

'I'he sheets to .be treated according to this invention may be made ofthe most varied types of material. Paper, of course, is one of the mosttypical materials. Besides paper, however, other sheet materials may beso treated, such as metallized paper, metal foil, cellulose compoundsand the like.

The invention may be used in practice in various physical embodiments.For example, in one embodiment of the invention the minute canals may beprovided by minute tubes, which may be placed in one or more rows anddisposed with their lower ends extending into the liquid; the materialto be treated is then passed over the upper ends of the tubes.

In another embodiment the canals may be provided by minute grooves.These grooves are not necessarily provided with bottoms For example, aliquid applying device in a form simulating a comb, in which the spacesbetween the "teeth" provide the minute canals, gives advantageousresults.

In another embodiment of the invention, the coating is applied to thesheet material in a multiplicity of minute streams by leading the liquidto the material in a multiplicity of canals in or on the surface of aroller, which may be either stationary or rotary. The canals areconveniently provided by grooves in the roller. 'Ihey may also beprovided by wires or the like which have been wound or otherwisearranged around the roller. If the roller is of the stationary type itneed, of course, not be a rotary body.

One of the important features of the present process, in which thedevice for applying the coating may be either stationary or rotary, isthat the amount of liquid applied per unit area of the paper may beregulated readily within the limits encountered in practice. When usingthe invention for treating ordinary papers, for eicample, it is possibleto apply less than 5 grams of liquid, and over 35 grams, per squaremeter of paper, and this without need for a heavy advanced run orcounter run. In case of pronounced roughness of the sheet and of greaterviscosity of the liquid, such as when preparing chromate coatings onrough metal surfaces, still larger quantities, such as 50 grams persquare mete'r and more, are obtainable. This regulation is effected'quite simply, namely, by regulating the distance between the surface ofthe liquid and the place where the sheet leaves the application device.This distance is referred to below as the .level distance. If the leveldistance is decreased, other constants remaining the same, a largerquantity of the liquid is applied,

and vice versa.

The level distance may be regulated very easily if it is dependent onthe height of the liquid in a liquid bath; in such a case, the liquidbath is connected with a liquid container which is located relativelyhigher or lower. The applying device consequently reaches more or lessinto the liquid. If a roller having a large diameter is used as theapplying device, it may be necessary to allow the roller` to run instuffing box glands, or to have the roller pins, the motion device andother parts extending into the liquid.

Another important feature of the new process is that it substantiallyimproves the starter. For instance, a starter may be obtained which hasa length of only a few centimeters and a size approaching unity. Ofcourse, it is not possible to obtain such ideal starters in all examplesof operations, but a great improvement over the known practices may beascertained in almost all examples, especially over practices involvingthe use of known roller devices at normal speeds. Of course, there is noimprovement with respect to the starter in comparison with the practiceof whirling chromate plates, but that process possesses otherdisadvantages, as mentioned above, with which the present process is notafflicted.

In this invention it is of special advantage 4 for instance, because ofthe appearance of ruptures, and when, in the case of a smooth roller. itwould be necessary to work either with a considerable advanced run orwith a counter run in order to obtain at least somewhat satisfactoryresults. This, of course, does not preclude the fact that in specialcases friction between the paper and the applying device may givespecific advantages,v for instance, a counter run for the application ofvery large amounts of liquid.

The special requirements which the minute canals as used according tothis invention must meet in certain cases depend on the nature of eachparticular case. Forexample, should the canals be too wide, the uid maynot be applied in a suicient amount. In this respect, the questionwhether capillary action must be relied on entirely for the provision ofthe liquid (as in the case of stationary applying devices), or whetherother means must provide' therefore (such as friction in the case ofrotary coating devices). or both, also should be considered. If thecanals are too far apart irregularities occur, while under certaincircumstances the process is no longer effective.

Further objects and advantages of the invention and details of preferredmanners f practicing the same will appear from the following moredetailed description, when considered ln connection with theaccompanying drawings, in which:

Cil

Fig 1 represents a cross section of an apparatus for applying a semi-wetcoating on a sheet according to the invention.

Fig. 2 represents a side elevation of a part of the roller I of Fig. l.

Fig. 3 represents a longitudinal section along a prole line of a part ofthe roller I of Fig. l on an enlarged scale.,

Fig. 4 represents a side elevation of an applying device having helicalgrooves.

Fig. 5 represents a cross section of a rolle'r the journals of which areimmersed in the coating liquid.

Figs. 6 and 7 represent an applying device similar to a comb, Fig. 6being a cross section and Fig. 7 a side elevation of a part thereof onan enlarged scale.

Fig. 8 represents a cross section of an apparatus provided with twoapplying rollers.

Figs. 9-16 represent graphical indications of various types of startersIn Fig. 1 the applying device in the form of a roller I is mounted in atrough 2 containing the iiuid 3 to be applied.' The sheet 4 is guided byguide rollers 5, the rollers I and 5 and the sheet I running in thedirections of the arrows. A vessel 6 mounted for vertical adjustment hasa iiexible communicating connection 'I with the trough 2 in order toenable the operator to increase or to decrease the level distance A.

In Fig. 2 Ithe parallel lines 8 represent the small grooves or canals inthe roller I of Fig. l, by which grooves or canals the uid from trough 2is applied to the sheet 4 (see Fig. 1). These grooves or canals areshown in Fig. 3 at a larger scale, p representing the period of thecanals.

Instead of crossing the axis of the roller vertically the canals 8 mayform a helical curve with reference to the axis of the roller, asrepresented in Fig. 4.

In Fig. 5 the roller I has its journals I0 immersed in the liquid 3 inthe trough 2.

In Fig. 6 the trough is again represented by the figure 2. It containsthe fluid 3 to be applied on the sheet 4, said sheet being guided byrollers 5 over the applying device II. As follows from Fig. 7 thisdevice is similar to a comb, parts I2 forming the teeth and the spacesI3 between the teeth forming the minute canals, without bottoms In Fig.8 the sheet 4 is guided by three guide rollers 5 over the applyingrollers I and I. Both rollers I and I' are provided with minute canalsas described in connection with Figs. 2 and 3; the level distance B ofroller I' is larger than that (A) of roller I.

The starter in Fig. 9 corresponds to the one which may be obtained froma process which is now mostly used, having smooth rollers and parallelmotion (same speed of sheet and roller in the same direction). Fig. 9therefore represents the status ol' the technique as to the process withparallel motion. In Fig. 10 the starter is shorter while being of likesize, the one in Fig. 11 is smaller while being of like length, and itmay, for instance, in mechanisms with counter motion (roller runs inopposite direction to paper) be obtained in accordance with theprevailing technique.

Fig. 12 represents a typical starter obtained by using the new process,said starter having a length of only a few centimeters and a size of1.05. l

The other graphs will be elucidated as the specification proceeds.

In a typical and simple example of performance of this invention, oneuses a roller surface with a profile reproduced in Fig. 3. The canals 8run around the whole of roller l. Calculated on one of the profile linesthe canals have a delinite total cross section per dm. of the length ofthe roller. In Fig. 3 this cross section is equal to the width of thecanals multiplied by their depth and again multiplied by their numberper dm. length. 'I'his entire cross section per dm. length of theapplication device is inidcated below by the word passage Experimentsshow that already with rollers of a small passage. for instance, ofabout 2 mm?, a considerable capability of regulating the amounts ofliquid to be applied has been achieved, which even surpasses the resultof a matt surfaced roller. A great improvement in the starter whenapplying amounts of liquid of about 10 g. per 1n.2 is achieved with apassage of about 20 to 30 mm3.

Conditions are similar in other examples of perfomance with respect tothe use of stationary as well as rotary application devices.

One may obtain a certain passage by means of a larger number of smallcanals or by means of a smaller number of large canals. In the formercase, the distance of the canals, the period p is small, in the lattercase large. Within certain limits, the effect in accordance with thisinvention is more or less independent of this variation. For practicalconsiderations, construction of device, accessibility for cleaning thecanals, and the like, one wi11,\of course, not choose any exceedinglysmall canals and periods, while the effect in accordance with thisinvention will, of course, be lessened with periods beyond a certainsize, whereby the liquid layer is applied in stripes of more and of lessliquid. This fact has already been pointed out. When using rollers withcanals placed vertically to the axis this condition becomes evident, forinstance, even when using a period of approximately 5 mm.; and whenstill larger periods are used, for instance of mm., it may preventoperation.

One may also obtain a certain passage by providing for narrow deep orbroad shallow canals. Also in this respect, practical limits are set tothe breadth and depth: to the depth, for instance, by the strength ofthe application device, to the breadth because too broad canals, same astoo large periods, may cause disturbances, such as the occurrence ofstripes, and the like. Breadths oi more than 0.5 mm., may already causedamage when applying fluids with a viscosity of about that of water.'I'he data given here are, however, no't absolute data as the appearanceof these disturbances is to a certain degree dependent on the leveldistance, i. e. to the eil'ect that a lessening of this distancecounteracts the appearance of stripes or tracks. Also an increase ofviscosity of the liquid has, for instance, an eii'ect in this respect.Besides, these disturbances are more of a hindrance for one kind of workthan for another.

Also the speeds of the sheet and of the roller, I if any, have a certaininfluence.

eiect that the advanced run applies less and the counter run more.

From the foregoing it must be deduced that the canals may show adifferent form of the cross section. I have already mentioned round andrectangular cross sections, they may also be in the shape of a V, whichform is named here because same is easily obtainable in practice. Canalswith a V shaped cross section in general produce the effect desired inaccordance with this invention, but sometimes in a lesser degree thanthe rectangular canals.

As a rule, one may say that the canals need not follow the line of theshortest distance between the level of the liquid and the place wherethe sheet leaves the application device. This means, for instance, withrespect to rollers, that the canals need not cross the axis of theroller vertically; they may, for instance, also -be arranged in thenature of a helical curve in or on the Surface of the roller, asrepresented in Fig. 4. One may also use canals cutting across eachother. As a borderline-case, one may in the case of rotary applicationdevices construct the canals in the longitudinal direction of thesedevices.

In general, one may also state that the starter is better when applyingsmall amounts of liquids than larger ones.

As a matter of fact the greatness of the effect obtained in accordancewith this invention depends on still other factors than those described.

for instance, on the composition of the liquid used, and the moisturecontent of the paper; this applies especially to the amount of fluidapplied per m?. At any rate, however, the improved eil'ect, incomparison with the use of a smooth or matt surfaced roller is evidentwhen other constants remain the same.

Compared to the process working with mattsurfaced rollers or withdevices having felt or brush surfaces, the process provided by thisinvention has also the advantage that the devices areless subject tobeing worn out and becoming dirty and they may be cleaned easily, whichfact applies especially to devices with open, easily accessible canals.

This invention is, of course, not limited to a process where theapplication device, for instance, a roller, is partly in the fluid,although this method of operation at the moment may be considered as themost practical one; one may. of course, also supply iluid to theapplication de- K vice in other ways, for instance, with auxiliaryrollers. The conception of level distance is then, of course, toberevised. This invention is also not limited to working with only oneapplication device; one may also work, for instance, with two or morerollers; also when supplying liquid several times to the sheet or alsowhen applying it once or several times on both sides of the sheet, thisinvention may be used to advantage.

This process is of special importance when applied to the so-calledsemi-wet method of preparing and developing, or to the semi-wet xing ofdiazotypes and blue prints and, for instance, when preparing chromategelatine or chromate gurn layers on leaves, sheets and the like, for thetechnique of printing, for instance, when preparing oifsets. In all ofthese processes it is important to obtain, from' the beginning, an exactand variable adjustment of the amounts of liquid overthe entire surface,according to the particular process being used.

Also, if layers, especially diazo layers, should be contained incellulose surfaces or should be applied.v therein, a good treatment ispossible in accordance with this invention which treatment very oftenmeets with difliculties when the usual smooth or matt surfaced rollers,i. e. rollers not provided with canals, are used, especially whenrunning parallel. It is surprising that it is possible to work inaccordance with these processes, without meeting with difficulties, bymeans of application devices provided with canals, and that thereby onemay obtain such technically important advantages.

The forwarding of the sheets may be accomplished with rollers; beforethe application of the layer of liquid, for instance, with rollers whichtouch the sheet on both sides; shortly after application by means of aroller touching only the untreated side; after the absorption oi theliquid into the sheet, again with two rollers, as before theapplication. If one applies small quantities, for instance g. per m?,one may let the forwarding device touch the treated side also almostdirectly upon application. @ne may also let the roller vapplying theliquid take the paper along itself or the roller may be taken along bythe moving paper. Furthermore, upon the application of the liquid, adevice may be so installed as to wipe oil the so-called stained edgekwhich may be sometimes found on the edge of the sheet, as well as ablotting roller, While the drying may also take place upon applicationof the liquid by means of a coupled drying device.

l stained edge especially occurs when the applying device is a rotatingroller and may be objectionable as soon as more than about 7 g. liquidper m.2 must be applied to the sheet. If, however, two or more applyingdevices are provided in such a manner that the last one [which is one ofa type provided by this invention] when working alone wouldfor the restunder the same condit-ions-apply less liquid on the sheet than thedevice adjusted before the last one when working alone in its turn, thestained edge is much. decreased and separate means for removing saidedge may be dispensed with. For reasons of an easy transport oi the endof the sheet a parallel-motion roller is preferably used as the nnalapplying device. This method is of special importance when developingdiazo type copies.

in principle, when applying the process according to the precedingparagraph, the applying device or devices adjusted before the nal oneneed not necessarily be of the type according to the present invention;they may rotate or stand still; when using rollers as these devices,said rollers may be smooth or matted. It is preierred, however, not onlyto provide the iinal applying device with minute canals in accordancewith the present invention but also the other ones. Preferably the lastmentioned ones have also the form of rollers and, when in use rotate inthe same direction and with. the same speed as the sheet travels(parallel motion).

lT-here are several Ymanners in which the apparatus can be built oroperated to the effect that the last applying device will apply lessliquid on the sheet than the preceding one in the sense" which hasalready been described. For example, this may be achieved by using a.roller as an applying device preceding the finaly one and operatingsaid roller with a. suicient countermotion; if said preceding roller isone according to the present invention an additional advantage isobtained; only a small starter is caused by said roller.

Another, very simple manner consists in regulating the quantity ofliquid ap-plied by the iinal applying device in relation to that appliedby the preceding one with the aid of the level distance of the finaldevice. If both iinal and preceding device are formed in accordance withthe present invention it is possible, of course, also to regulate thequantity of liquid supplied by the preceding device by means of itslevel distance; if in Ithis case two similar rollers are used thisamounts to arranging the preceding roller so that it works with asmaller level distance than the nal one (Fig. 8: the level distances areA and B) `If in the last mentioned embodimentl thev difference in leveldistance amounts to more than 10 mm., spots may be found on the sheet. Adiierence in level distance between 3 and 7 mm., for example a,difference of 5 mm., has proved to yield good results,

If the measures described above for decreasing the stained edge arechosen well, :two applying devices, for example two rollers, are nearlyalways sumcient. This is of practical importance as this is simpler thanthe use of more applying devices.`

The application devices of the present invention may loe prepared fromany material suitable therefor, for instance, from suitable metals whichmay, if desired, be provided with corrosion-resistant surfaces, such aschromium, and the like. Also, stainless steel is especially suitable;furthermore glass, synthetic resins, hard rubber, and the like may beused. in most instances, when a roller is used, same is drivenmechanically. In. case of appliances without a motor, one draws thepaper across the roller and this then turns the roller. The starter isthen generally less beautiful, but one still gets the advantages of thepresent invention.

The following examples may illustrate the invention. For simplicityssalie, one has always worked with an applier placed in a troughcontaining a fluid, which permits the level distance to be expressedmore exactly in figures. For conveniences sake, one takes here as thelevel distance the vertical distance between fluid level and the linewhich has been drawn parallel to this level through the place where thesheet leaves `the applier (Fig. l, distance A).

Example l A sheet made of the usual suitable raw material paper of g.per :n.2 with a pH of approXirnately d, which 'was prepared in the usualmanner with approximately l5 cm.3 per m? of a solution of Per centp.Diazo-ethyl benzyl aniline chloride 2 Thio urea 3 Oxalic acid 1Gelatine 0.2

and then dried to a moisture content of approximately 3%, is exposedunder a transparent original and thereupon developed with a solution ofSodium salt of isopropyl naphthalene sulfonio acid 0.1

. developing roller has In the process of developing, the sheet runsover a mechanism as reproduced diagrammatically in the cross section ofFig. 1. Roller l and sheet 4 run both in the direction of 'the arrowswith a speed of 2 m, per minute. The roller has a diameter of 35 mm. andis provided with small canals in accordance with Fig. 3. 'I'he smallcanals have a width of 0.4 mm., a depth of 0.6 mm. and a period p (Fig.3) of 0.8 mm., so that the passage amounts to 30 min.2 per dm. lengthThe level distance A is 10 mm. In this manner, the developer isdistributed over the sheet as shown in Fig. 13, whereby a good blackdevelopment of the diazo type copy is obtained with about 12 `g. per m?.The starter is about 1.2 and has only a length of approximately 9 cm. I!one addsto the developing fluid 1%% of glycol mono butyl ether, one mayobtain a similar development with a still smaller and shorter starterand a little larger uid quantity per m3: or with the same uid quantityat a somewhat lesser speed or a somewhat greater level distance.

Example II One works as described in Example I with the developerwithout glycol mono butyl ether. but with small canals'having a breadtho! 0.25, a depth oi' 1.2 and a period ot 0.6 mm., i. e. with a passageof 50 mm.z per dm. length. One then obtains the results stated in thetable below which have been reproduced in curves in Fig. 14.

Speed oi sheet Quantity ffm and roller (par starter of liquid crielnalle] run per ml Mm. Grams 10. 4 m. per sec Size 1.1, length :14 u

-.-- 6 m. per sec..- :t5 cm.

10..-- 2.7 xn. per sec-- Size 11.05, length i12 b 15.--- 4.1m. persec.-:h3 cm.

15...- 1.4 m. per sec-. }Size 1.0, Length: :HM c

... 4m.persec...- nil.

I! one works in accordance with a, one may. for instance, dilute thedeveloper with about 15% water which may be desirable in cold weather.It one works in accordance with c, one may take about 4% oi' soda inlieu of 3% and one then obtains a quicker drying print oi' a somewhatbrowner color.

Example III One makes the preparation as mentionedy in Example I with asolution of:

Sodium salt of iso propyl naphthalene sul- Ionic acid 0.1 As describedin Example I, for this development the sheet runs over a rotary roller.The

sheet has a speed oi' 2 m. per minute and the a speed of 0.8 m. perminute (backward run). The roller has a diameter of 35 mm. and smallcanals, as shown in Fig. 3.

'Ihe small canals have a breadth of 0.25 mm.,

a depth of 1 mm. and a period o1' 0.6 mm. and

consequently a passage of about 40 min. per dm.

length. The level distance is 28 mm.

In this way, one obtains a good development with about 51/2 g. of thedeveloper per ni?. obtaining a very good starter.

Example I V One makes the preparation as shown in Example III but onedevelops with ammonia liquid having a speciilc weight oi 0.90. 'I'hedevelopment is made as follows:

Roller and sheet are both running with a speed of 2.3 m. per minute inthe same direction (parallel run). 'I'he roller has a diameter 0f 25 mm.and is provided with canals as shown in Fig. 3. These have a breadth of0.25 mm., a depth of 0.8 mm. and a period of 1.2 mm. so that the passageis :16 mm.I per dm. length. The level distance is 20 mm. One obtains abeautifully black developed print, while the quantity applied amounts to7 g. per m.n The starter is practically not much bigger than the oneshown in Fig. 14.

One may carry through this development in a closed vessel in order toavoid the annoyance of ammonia vapors, in which the developed print mayalso be de-aerated. Since the quantity o! iluid applied is only small,one may touch both sides of the print shortly after application andtherefore forward it with rollers or other meana Example V One makes thepreparation as described in Example II but with a solution of:

Percent Diazo-l-benzoyl amino-4-diethoxy-2-5-benzol chlorostannate 2.5Citric acid--- Boric acid.

and develops with a solution of:

Soda Phloroglucinol Pax.

1 0.5 Sodium salt of iso propyl naphthalene suli'onic acid 0.1

Per cent Ezample VI One makes the preparation as ln i Example I, butwith a solution of Per cent Ferrie ammonium oxalate 8 Potassium -ferriccyanide 4 Secondary sodium phosphate 2 Gelatine-.. -s 02 and iixes witha solution ot:

aefiiuo'a 7 I Percent mm., so that the passage amounts to a littlePrimary ammonium phosphate 10 over 30 mm2 per dm. length. Phosphoricacid spec. weight 1.3 3 The roller rotates in a small trough contain-Zinc sulfate 10 ing a fluid of: Ammonium persulfate 5 Parts by weightSodium salt of the sulfuric acid ester of the Potassium bichrornate 6oleic acid butyl ester 0.1 and For this iixation,` the-sheet runs in anappagummi arablcum 23 ratus 1n accordance with Fig. 1 over a roller mDistilled Water 100 which, however, rotates in opposite direction to thesheet. The sheet has a speed of 2 m. per minute, the roller one of 31A;m. per minute (in opposite direction). The roller is the same asdescribed in Example III. The level distance amounts to 10 mm. Thedistribution of the xing agent over one sheet is shown in Fig. 15. Thequantity amounts to about 35 g. per m.2 with a starter of about 1.25(35:28) and length of about 10 cm. One obtains a negative blue print inlight cream-yellow line on a dark blue background which shows inpractice a sufficiently great stability to light.

Example VII One prepares row material paper of the kind as indicated inExample I but With a somewhat rougher surface, i. e. in the customarymanner per m? with about cm.3 of a solution of Per cent Para-diazo ethylbenzyl aniline chloride 1.3 Thio urea 3 Oxalic acid 1 Gelatine 0.2

Example VIII Paper is prepared and developed with the uids disclosed inExample I. When developing, the sheet runs over a stationary metaldevice Il, which reaches down into the developing fluid 3, as shown inFig. 6. As appears from the longitudinal cross section shown in Fig. 7the device has the shape of a comb; its thickness is 2 mm. With aperiodv of 2 mm. canals I3 are provided having a. breadth of 0.25 mm.and a depth of 15 mm. The level distance amounts to 10 mm. and the paperhas a speed of 4 m. per minute.

The result of this development is as shown in Fig. 16. The starter isabout 1.2 and has only a length of about 5 om. v

By regulating the level distance and the speed of the paper, one mayregulate the quantity of uid applied in a similar manner as in ExampleII.

Example IX A matt-surfaced aluminum sheet, pasted on paper, as is usedfor oiset machinesI in offices, is passed with a speed of 2 m. perminute over a roller having a diameter of 35 mm. which roller isprovided with small canals in eaccordance with Fig. 3. The small canalshave a period of 0.6 mm., a breadth of 0.4 mm. and a depth of 0.5

The temperature of the solution amounts to about 20 degrees C. The leveldistance is 8 mm. At a Speed of the roller of 1.5 m. per minute(therefore with a small backward run) about g. of fluid per m.2 isapplied; at a roller speed of 2 m. per minute (in the same direction)about g. are applied. If one gives the roller a speed of 2.5 per minute(i. e. small advanced run) one applies about g, fluid per m.2. (In thiscase, the somewhat greater viscosity of the uid causes apparently asmall deviation from the rule that less is applied vwhen applyingadvanced run.)

After drying, the aluminum Sheet is ready for further preparation forthe offset type of the oiiice machines.

The starter obtained in this manner is without importance. If one worksunder the same conditions with a smooth roller one does not obtain auniform preparation of the aluminum sheet.

One may also Work with other rollers, for instance, with a roller havingsmall canals with a period of 0.6 mm., a Width of 0.25 mm. and a depthof 0.6 mm.; therefore with a passage of 25 mm.2 per dm. length. Due tosuch a small cross section of the canals there is, however, a littletendency, in parallel runs at any rate, to form small air bubbles on theprepared surface.

With a roller having V-formed canals of 37 degrees and a width of 0.4with a period of 0.4, in other Words with canals lying next to eachother, one obtains good results even in parallel runs.

In connection with the viscosity of the fluid it is to be stated thatthese results, of course, ca nnot be obtained at any low temperaturewhatsoever.

Example X An acetyl cellulose lm of approximately g. per m? is saponiedon one side and prepared on the saponied side with a solution of 5%paradiazo ethyl benzyl aniline chloride and 2% tartaric acid. Upondrying, a copy is prepared on this film either by transmitted light orby the usual reectography or in the manner of the screen reectography,whereupon the film is pasted on paper by means of casein in dilutedlatex. For this purpose, the side of the film to be pasted on isprovided with a thin layer of this latex solution and the paperlikewise. After both layers are dry, they stick together by themselveswhen pressed well.

'I'he film pasted on in this manner is noW- developed with the developerin accordance with Example I in an apparatus having a roller as used inExample III. The lever distance is 12 mm. and the sheet and the rollerboth run With aspeed of 2 m. per minute (parallel run). [It is alsopossible to use a small backward run (roller speed 1.5 m. per minute) ora small advanced run (roller speed 2.5 m. per minute) l.

Without any hindering starter, a 12 g. per In2 developer is appliedwhich gives a beautifully black copy. No usable result was obtained withthe aid of a smooth roller with other constants remaining the same.

Instead of taking a film of 55 g. per m2 and pasting same, one may takea hlm of 100 g. per m.2 which is not necessary to paste.

Eample XI One works as in Example I using, however, the apparatus whichhas been shown in Fig. 8. The rollers I and l and sheet 4 are allrunning with a speed of 2.3 m. per minute in the direction indicated bythe arrows. Rollers l and i have a diameter of 25 mm. and are bothprovided with rectangular canals (Fig. 3) having a breadth of 0.3 mm., adepth of 1.2 mm. and a period of 1.0 m-m. so that the passage amounts to36 mm.2 per dm. length of the roller. The level distance A is 12.5 mm.,the level distance B is 17.5 mm. In this way 11 g. of liquid per m? ofthe sheet are applied; the starter is very small and short and the sheetleaves roller 4 almost without stained edge.

If both rollers had worked with the same level distance, for example ofl5 mm., then the stained edge would have been greater and it would havebeen recommendable to take measures for removing same, for example bywiping, blotting, additional drying and so on.

Furthermore an operation along the lines of this example gives less riseto an unequal supply of liquid on the sheet on account of unevennessesin the sheet than does a process in which only one 4 roller is used.

Of course it is also possible to have rollers l and I running inseparate troughs.

What I claim is:

1. A method of developing or fixing light-sensitive sheets of any lengthaccording to the socalled semi-wet process which comprises leading adeveloping or xing liquid from a supply thereof to a zone of applicationin a multiplicity of closely-spaced minute streams and passing the sheetover said zone in contact with said liquid in said zone. said streamsbeing spaced apart such a small distance that a substantially uniformquantity of the liquid is applied over the width of the sheet.

2. A method according to claim 1, characterized in that the sheet ispressed freely over said zone.

3. A method of developing or ilxing light-sensitive sheets of any lengthaccording to the socalled semi-wet process which comprises leading adeveloping or fixing liquid from a supply thereof to a zone ofapplication ih a multiplicity of closely-spaced minute streams ofrectangular cross-section and passing the sheet over said zone incontact with said liquid in said zone, said streams being spaced apartsuch a small distance that a substantially uniform quantity of theliquid is applied over the width of the sheet.

4. A method of developing or fixing light-sensitive sheets of any lengthaccording to the socalled semi-wet process which comprises leading adeveloping or iixing liquid from a supply thereoi.' to a zone ofapplication in amultipllcty of closely-spaced minute streams of a Vcross-section and passing the sheet over said zone in contact with saidliquid in said zone, said streams being spaced apart such a smalldistance that a substantially uniform quantity of the liquid is appliedover the width of the sheet.

5. A method of developing or fixing light-sensitive sheets of any lengthaccording to the socalled semi-wet process which comprises leading adeveloping or iixing liquid from a supply thereof in a multiplicity ofclosely-spaced minute streams to an elongated zone of applicationextending transverse to said streams and passing the sheet over saidzone in Contact with said liquid in said zone, said streams having atotal cross section of at least 2 mm.2 per dm. of length of said zoneand being spaced apart such a small distance that a substantiallyuniform quantity of the liquid isapplied over the width of the sheet.

6. A method of 4developing or iixing light-sensitive sheets of anylength according to the socalled semi-wet process which comprisesleading a developing or fixing liquid from a supply thereof to a zone ofapplication in a multiplicity of closely-spaced minute streams andpassing the sheet over said zone in contact with said liquid in saidzone, said streams being spaced apart with a period of less than 15 mm.such lthat a substantially uniform quantity of the liquid is appliedover the Width of the sheet.

'7. A method of developing or fixing light-sensitive sheets of anylength according to the socalled semi-Wet process which comprisesleading a developing or iixing liquid from a supply thereof to a zone ofapplication in a multiplicity of closely-spaced minute streams andpassing the sheet over said zone in contact with said liquid in saidzone, said stream being spaced apart with a period of less than 5 mm.such that a substantially uniform quantity of the liquid is applied overthe Width of the sheet.

8. A method according to claim 1 in which the minute streams of liquidare united into a thin band of liquid extending transverse to thedirection of movement of the sheet at said zone of application.

9. A method of developing or fixing light-sensitive sheets according tothe so-called semi-wet process which comprises leading minute streams ofa developing or fixing liquid from a supply thereof by a multiplicity ofclosely spaced minute canals on the periphery oi a roller to a zone ofapplication on said roller, passing the sheet over said zone in contactwith said liquid in said zone, Iand simultaneously rotating said roller,said streams beng spacedapart such a small distance that a substantiallyuniform quantity of the liquid is applied over the width of the sheet.

10. A method of developing or fixing lightsensltive sheets according tothe so-called semiwet process which comprises leading minute streams ofa developing or fixing liquid from a supply thereof by a multiplicity ofclosely spaced minute canals on the periphery of a roller to a zone ofapplication on said roller, passing the sheet over said zone in contactwith said liquid in said zone, and simultaneously rotating said rollerin the direction of movement of said sheet and at a correspondingperipheral speed, said streams being spaced apart such a small distancethat a substantially uniform quantity of the liquid is applied over thewidth of the sheet.

11. A method of developing or xing light-sensitive sheets of any lengthaccording to the socalled semi-wet process which comprises leading adeveloping or fixing liquid from a supply thereof to a zone ofapplication in a multiplicity of closely-spaced minute streams, passingthe sheets over said zone in contact with said liquid in said zone, andregulating the amount of liquid applied to the sheets by varying thedistance between said zone and the level of the liquid supply, saidstreams lbeing spaced apart such a small vdistance l that asubstantially uniform quantity of the liqlight-sensitive sheetsaccording to the so-called semi-wet process, means adapted to be held incontact with a supply of developing or fixing liquid for applying alayer thereof onto the sheets,

saidmeans having the shape of a comb the teeth of which formclosely-spaced minute channels therebetween, said channels extendingbetween the liquid supply and a zone of application spaced therefrom andbeing spaced apart a distance sufilciently small to apply asubstantially uniform layer of the liquid over the width of sheetspassed across said zone. y

13. Apparatus for developingv or fixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising containerfor holding a supply of developing or fixing liquid and means in contactwith the supply liquid for applying a layer thereof onto the sheets.said applying means comprising at least two rollers arranged in spacedrelation with their axes horizontal and each having a multiplicity ofcloselyspaced minute channels on its periphery forming a connectionbetween the supply liquid and a zone of application spaced therefrom,the channels of each roller being spaced apart adistance suilicientlysmall to apply a substantially uniform layer of the liquid over theWidth of sheets passed across the corresponding zone of application,said zone of the final roller being at a greafter distance from thesupply liquid than said zone of the pre- -ceding roller.

14. Apparatus for developing or fixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising a rigidmember for applying developing or xingliquid to the sheets and means forsupplying such liquid to said member, said member formed with capillarymeans for leading such liquid in a multiplicity of mintue streams fromthe liquid supply to a zone of application spaced therefrom, saidcapillary means comprising a multiplicity of closely-spaced minutecanals of such small width and so closely spaced as to apply asubstantially uniform layer of the liquid over the width of sheetspassed in contact with liquid in said zone.

15. Apparatus for developing or fixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising a rigidmember for applying developing or fixing liquid r to the sheets andmeans for supplyingl such liquid to said member, said member formed withcapillary means for leading such liquid in a mulrtiplicity of minutestreams from the liquid supply to a zone of application spacedtherefrom, said capillary mean-s comprising a multiplicity of separate,closely-spaced, parallel, minute canals having open sides in a commonplane extending from such supply to said zone and of such small widthand so closely spaced as to apply a substantially uniform layer of theliquid over the width of sheets passed in contact with Iliquid in saidzone.

16. In an apparatus fordeveloping or fixing light-sensitive sheets ofany length according to the so-called semi-wet process, means forapplying developing or ilxing liquid to the sheets comprising a rolleradapted to be contacted by a supply of the liquid and having on itsperipherycapillary means for leading the liquid in minute streams fromsuch supply to a zone of application spaced therefrom, said capillarymeans comprising a multiplicity of minute parallel canals open at theperiphery of the roller and of such small width and so closely spaced asto apply a substantially uniform layer of the liquid to sheets passed incontact with liquid in said zone.

17. In an apparatus for developing or fixing light-sensitive sheets ofany length according to the so-called semi-wet process, means forapplying developing or fixing liquid to the sheets comprising a rolleradapted to be contacted by a supply of the liquid and having at itsperiphery capillary means for leading the liquid in minute streams fromsuch supply to a zone of application spaced therefrom, said capillarymeans comprising a multiplicity of minute parallel canals open at theperiphery of the roller and of such small Width and so closellT spacedas to apply a substantially uniform layer of the liquid to sheets passedin cont-act with liquid in said zone, said canals extending verticallywith respect to the axis of said roller.

18. In an apparatus for developing or fixing light-sensitive sheets ofany length yaccording to the so-called semi-Wet process, means forapplying developing or iixing liquid to the sheets comprising a rolleradapted to be contacted by a supply of the liquid and having at itsperiphery capillary means for leading the liquid in minute streams fromsuch supply to a zone of application spaced therefrom, said capillarymeans' comprising a multiplicity of minute parallel canals open at theperiphery of the roller and of such small width and so closely spaced asto apply a substantially uniform layer of the liquid to sheets passed incontact with liquid in said zone, said canals defining a helical curvewith respect to the axis of said roller.

19. Apparatus for developing or xing lightsensitive sheets of any lengthaccording to the so-called semi-Wet process comprising a rigid memberfor applying developing or fixing liquid to the sheets, having amultiplicity of separate, closely-spaced, minute canals adapted to forma connection between a supply of such liquid and an elongated zone ofapplication spaced therefrom and operative to lead the liquid bycapillary action to said zone in a multiplicity of minute streams, saidcanals having a total cross-sectional area of at least 2 mm.2 per 100mm. of length of said zone, having a period of less than 5 mm. and beingso closely spaced as to apply a substantially uniform layer.. of theliquid to sheets passed across said zone in contact `With liquidtherein.

20. Apparatus for developing or fixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising a rigidmember for applying developing or fixing liquid to the sheets, formedwith a multiplicity of separate, closely-spaced minute canals adapted toextend between a supply of such liquid and an elongated zone ofapplication spaced therefrom and operative to lead the liquid bycapillary action to said zone in a multiplicity of minute streams, said`canals being of rectangular cross- I section and being so closelyspaced as to apply a substantially uniform thin layer of the liquid tosheets passed across said zone in contact with liquid therein.

2l. Apparatus for developing or fixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising a rigidmember for applying a developing or fixing liquid to the sheets, formedwith a multiplicity of separate, closely-spaced minute canals adapted toextend between a supply of such liquid and an elongated zone ofapplication spaced therefrom and operative to lead the liquid bycapillary action to said zone in a multiplicity of minuts streams, saidcanals being of V-shaped cross-section and being so closely spaced as toapply a substantially uniform thin layer of the liquid to sheets passedacross said zone in contact with liquid therein.

22. Apparatus for developing oriixing lightsensitive sheets of anylength according 'to the socalled semi-wet process comprising a rigidinember for leading developing or fixing liquid from a supply thereofand for applying the liquid directly to the sheets, said rigid member:formed with a multiplicity of separate, closely-spaced minute canalsadapted .to extend between such supply and a zone of 'application spacedtherefrom and operative to lead such liquid by capillary action to saidzone in a multiplicity of minute streams, said canals each having aWidth not exceeding about .4 mm., said canals being so closely spaced as-to apply a substantially uniform thin iilm of the liquid to sheetspassed over said zone in contact with liquid therein.

23. Apparatus for developing or iixing lightsensitive sheets of anylength according to the so-called semi-wet process comprising a rigidmember for leading developing or xlng liquid from a supply thereof andfor applying the liquid in a uniform thin iilm directly-to the sheets,said rigid member formed with a multiplicity of closely-spaced minutecanals adapted to extend between such supply and anelongated zone ofapplication spaced therefrom and operative toV lead such liquid to suchzone in a multiplicity of minute streams, said canals having a periodnot 1.2 mm.

24. Appamtus for developing or fixing lightsendtive sheets of any lengthaccording tothe socalled semiswet process comprising a rigid member forleading developing or fixing liquid from `a suppiy thereof and forapplying the liquid in a uniform thin film directly to sheets passedthereover in an elongated zone of application spaced from such supply, aface of said member adapted to extend between such supply and such zonehaving formed therein a multiplicity of closely-spaced minute canals ciat said iace and operative to lead liquid 'to s id sone in amultiplicity of minute streams, each. of said canals having a Width notexceeding .fl nini. anni said canals having a total cross-sectional notexceeding about 50 mm.2 per 100 mm. of length oi said zone.

245. Apparatus :for developing or xing lightsensitive sheets of anylength according to the so-called semi-wet process comprising acontainer for holding a supply of developing or lixing liquid, a rollermounted for rotation about a horizontal aids in contact with liquid insaid container and sheet feeding means for passing sheets freely acrosssaid roller at a zone oi its periphery spaced above the level of contactwith liquid in said container, the periphery of said roller formed withcapillary means for leading liquid in a multiplicity of minute streamsfrom such supply to said zone, said capillary means comprising amultiplicity of minute, parallel canals extending transverse to the axisof said roller and open in a common plane at -the periphery thereof,said canals being of such small width and so closely spaced as to applya substantially uniform layer of liquid to sheets passed across saidzone in contact with liquid therein.

LODEWIJK PIETER'FRANS van Dan GRINTEN.

